The invention relates generally to the control of a machine for automatically sizing and filling food casings, and, more particularly, to a method and apparatus for aligning labels on shirred food casings as the casings are being filled and clipped.
Food products such as sausage and other processed meats, cheese, sandwich spreads and the like are often packaged in tubular casings which are tied, clipped or otherwise secured at both ends. Larger size packages (e.g., one to three pounds) are known in the industry as chub packages.
Chub packages are typically made of fibrous material, polyethylene film, saran film, or a combination of polyethylene film and saran film. The film is typically stored on a roll, and is shirred into strands prior to filling. Usually two or more plies of film are used, and at least one ply is imprinted with information about the product. Thus, the film functions both as a package and as a permanent label for the product.
The shirred casing strands are placed on the stuffing horn and sizing ring of an automatic sizing and stuffing machine. The leading end of the first casing is clipped closed and food, in the form of an emulsion, is pumped through the stuffing horn. As each casing is filled, the shirred casing is pulled off the stuffing horn by the force of the food flow. Each casing is clipped to make individual chub packages. It is desirable that the imprinted label be centered between the end clips of each filled casing.
Various methods and machines are known in the art related to the controlling of machines which shirr and/or fill food casings. In U.S. Pat. No. 2,949,371 (Freund II, et al.), for example, a method and apparatus are disclosed for distinguishing between encased and skinless frankfurters. The invention incorporates longitudinal regenerated cellulose stripes in sausage casings, which stripes have characteristics different than the casing cellulose itself. The stripes are detectable and are used to distinguish encased frankfurters from skinless frankfurters. This patent does not address the additional problem of centering a label imprinted on an individual casing.
U.S. Pat. No. 3,112,516 (Bonnee) discloses a control for a shirring machine which uses a mechanical means to detect a splice in unshirred casing. Again, this patent is not concerned with casings having labels and with the problem of centering the labels between end clips.
U.S. Pat. No. 4,580,316 (Kollross) discloses a machine for automatically manufacturing shirred sausage casings which includes means for measuring register marks on the casings. However, the shirred casings of this invention do not include imprinted labels and hence there is no problem of interference between the register marks and a label.
U.S. Pat. No. 4,625,362 (Kollross et al.) discloses a method and device for automated manufacture of strings of sausages which incorporates a photocell for sensing sealing joints in shirred casings. However, the shirred casings of this invention are not imprinted with labels, and hence there is no interference problem between the sealing joints and the labels.
It has previously been impossible to accurately center printed blocks between endclips applied by automatic sizing machines. Such machines typically used product length, elapsed time, or pump metered portioning of products to control chub size. None of these methods accurately provides for centering printed blocks between endclips. Thus, a need has existed for a method and apparatus for centering imprinted labels on filled food casings between endclips, which casings are shirred prior to filling.